I already have the answer for the domain and range, I just need the equations! Pls, help!

What situation is an example of an observational study

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

20 points for the brainliest? drag each tile to the correct box. not all tiles will be used. arrange the steps to solve the equation . plz